Over the years, a variety of different spectrometers for inspecting the energy of secondary electrons and/or backscattered electrons in scanning electron microscopes have been developed. These spectrometers, can only be arranged outside of the electron optical systems due to their size and geometry and also due to the fact that they need to be disposed close to the object in order to collect as many particles as possible.
However, arranging the spectrometer outside of the electron optical system and close to the object involves the objective lens to be positioned at a comparatively large distance from the object. The large distance between the objective lens and the object leads to increased aberrations of the primary beam and, hence, imposes a limit on the attainable spatial resolution of the scanning electron microscope.
Therefore, a need exists for providing a particle beam microscope, which includes a detector system having a compact design and which allows to efficiently filter particles according to their energy.